Malware is software used for data theft, device damage, harassment, etc. It is very similar to computer malware. It installs things such as trojans, worms, and botnets to the affected device. It is illegal to knowingly distribute malware.

Drive-by-download

Rootkit

A rootkit is a stealthy type of software, typically malicious, designed to hide the existence of certain processes or programs from normal methods of detection and enable continued privileged access to an operating system.